Posted
by
kdawson
on Saturday August 07, 2010 @06:11PM
from the many-titanics-worth dept.

suraj.sun sends word of a 100-sq.-mile (260-sq.-km) ice island that broke off of a Greenland glacier on Thursday. "The block of ice separated from the Petermann Glacier, on the north-west coast of Greenland. It is the largest Arctic iceberg to calve since 1962... The ice could become frozen in place over winter or escape into the waters between Greenland and Canada. ... [NASA satellite] images showed that Petermann Glacier lost about one-quarter of its 70-km-long (43-mile) floating ice shelf. There was enough fresh water locked up in the ice island to 'keep all US public tap water flowing for 120 days,' said Prof Muenchow." The Montreal Gazette has more details and implications for Canadian shipping and oil exploration, along with this telling detail: "the ice island’s thickness [is] more than 200 metres in some places... [or] half the height of the Empire State Building." The NY Times has a good satellite photo of the situation.

Volume of a 15 x 2 x 3 cm chocolate bar: 9e-5 cubic metres
Volume of an Olympic swimming pool: 2.5e3 cubic metres
Volume ratio is 1 : 2.78e7
Total volume of the oceans is 1.3e18 cubic metres
Iceberg volume, in the same ratio as chocolate bar : swimming pool, would be 4.68e10 cubic metres
If the iceberg is 200 m thick, then the area is 234 square kilometres.
The area of the iceberg, according to the article, is 260 square kilometres
O.o
You, sir, have astounding powers of estimation.

That was kind of a weird comment. Nobody knows exactly what's going to happen because this hasn't happened in living memory. What would you have to gain with a "nothing to see here"?

Clearly, you have never seen how much excitement a candy bar in a swimming pool actually causes. Think about it for a minute. It will come to you. If it doesn't, what else might one find in a swimming pool that is about the same size, shape, and color as a candy bar?

I'm curious what technical challenges would have to be overcome to actually recover this frozen water. Many parts of the world are undergoing severe freshwater shortages. A very large block of frozen water seems like it could be very useful to answer that problem. Could getting at least part of it into into a reservoir be technically / economically possible?

Off the top of my head, I was musing about getting it into the Great Lakes, but the channels and locks in the Great Lakes Waterway are obviously far

I don't think you have any idea just how big this is. That is 10 miles by 10 miles. It is an iceberg as well. That means it is probably a couple hundred feet below the surface of the water as well.

Assuming just 100 feet deep in the water we are talking about 2,069,680,199,348 gallons of water. The largest dry dock in the world could barely hold a percentage of that mass. You would think you could split it up with explosives, but it would be a very dangerous endeavor requiring a huge amount of explosive

actually it looks like its about... 25km long, and about uh.. 7-9 km wide at its widest point. its 200m thick, and ice tends to do that 2/3rds of it is underwater thing, so about 400 feet of it are under water. This is not to say that you further examples are flawed, just that the berg is *HUGE*

Well if this is proof of global warming, then a snowstorm in the summer must be proof there is no global warming right? Or is climate different from weather?

This is something that has always annoyed me about the GW debate (or more like GW screaming match). When something bad happens, a glacier breaks off, there's a strong hurricane, or when the weather is unseasonably hot people say "See? See! Global warming! Look at the bad shit happening!" However when the opposite is true, when things are unseasonably co

Out of curiosity, can you point to any specific individual who wants to have it both ways, or is the problem that both sides are composed of a small number of rational people, and a lot of screaming loons?

I'm not a loon, it really is an envirocommunist worldwide conspiracy to overthrow the illuminati oil-lords. That only seems far fetched to those who uses non-rectal sources for their news. Step back a bit, look at the situation as a whole, and forget about the day to day details (facts at a high enough rate are just noise), then pull out a theory. Your colon can come up with interesting patterns, and facts are unnecessary ingredients for their assemblage.

This is something that has always annoyed me about the GW debate (or more like GW screaming match). When something bad happens, a glacier breaks off, there's a strong hurricane, or when the weather is unseasonably hot people say "See? See! This event counters your 'unseasonably cool' argument. Are you still going to denie Global warming! Look at the bad shit happening!" However when the opposite is true, when things are unseasonably cool, or when the weather is nice and mild (so far this year's hurricane season is shaping up to not be that intense) the screams are "Weather is not climate! You cannot look at isolated events and try to use them as proof!"

The "See? See!" quote is not a proof of GW, but a counter-proof to every "Weather is climate" denialists claims. Next time add in the bold yourself, now that you know what they really meant.

I can hear the commenters all across the internet now - "I've never studied anything about the arctic or the antarctic ice caps, climatology, or for that matter earth sciences in any real depth, but I KNOW this is proof of (insert really bad thing here)!"

Of course, to save time, most folks leave off the pre-amble and get right to the "I KNOW this is proof of (insert really bad thing here)!" (The not knowing what you are writing about is just assumed...)

I know they have some serious water supply problems in Africa... so... thoughts on just how hard it would be to tow this thing there? What are the challenges beyond boat power and grappling such a large yet fragile mass? How much would melt by the time it arrived?

I know they have some serious water supply problems in Africa... so... thoughts on just how hard it would be to tow this thing there? What are the challenges beyond boat power and grappling such a large yet fragile mass? How much would melt by the time it arrived?

Well, this is true for lots of areas, not just Africa. If Australia suddenly had a LOT more water, look at all that western land they could irrigate, a'la California. The problem with just towing it is that even if you get most of it where you want, you still have the problems of getting the water ashore, and of coastal temperatures dropping rapidly.... but temporarily... and affecting local sea life.

The better thing then would be to build more coastal desalinators and simply pump the fresh water inland via

Gets used here.... alot.Arguments both for or againsts a scientific problem should be framed as defendable proofs.We know that the top of Earth's atmosphere receives 342 watts of energy, in the form of sunlight, per square meter. Note that 107 W/m2 of this energy is reflected or scattered back into space by clouds, the atmosphere, and high-albedo features on Earth's surface. So, only 235 W/m2 (342 - 107) of energy actually make it into the atmosphere, and shines down upon us giving me women in miniskirts and the ability to grow food (both of which are....awesome)Furthermore, we know that 67 W/m2 of the incoming energy is absorbed by the atmosphere, and another 168 W/m2 is absorbed by Earth's surface. When energy is absorbed, it raises the temperature of the substances that absorb it (the atmosphere and surface of our planet, in this case); this causes those substances to radiate away that heat in the form of IR radiation. We can all agree that these are not simply my opinions right? For those of who are are unfarmiliar, these are called facts, lets keep going.About 390 W/m2 of IR energy starts upward from the surface, this difference being caused by longwave radiation needing an atmospheric window that does not have a lot of water vapor or gas molocules containing three or more atoms (i realize this is incomplete, i am atempting to simplify). The more of these conditions present in our atmosphere, the harder it is for longwave radiation to escape. So when we spew into the environment, and what we need to agree on is that adding vapor and GHG's to the environment increases the GW potential... right? Keep your fucking anecdotes to yourself, Using these things called facts we can see that keeping equilibrium becomes more difficult when we insist on changing the atmosphere. So don;t tell me you got two colds last year and only on this year so we are getting warmer, or that your uncle your uncles garden got frosted early thid year so we are geting colder. Or about ICEBERGS, this is an atmospheric issue, give me meaningful data about that and i will listen. Anyone who thinks that chnging the composition of our atmosphere will not result in temp change needs to back to school.

Thank you. This is what we need for meaningful discussion, not ranting and raving about various one off pieces of 'evidence' And of course, once again, I find myself reiterating my stance on "fixing' AGW.

Anything We Do To Fix It, Must Not Cause Harm IF We Are In Error.

seriously, In the last year, I have seen, here on/. as well as from many other news sources, the following ideas:
1. genetically re-engineering kangaroos to not pass methane.
2. genetically re-engineering cows to not pass methane.
3. spr

That's beautiful, except the 1300 watt figure is already an average. I'm by no means an expert, but I have had a long time interest in solar PV, and the energy at the surface where I live for a flat plate collector aimed at solar noon is quite close to 1000 watts per square meter. Now, a mono or plycrystalline silicon panel, with its indirect bandgap absorption is only going to collect something on the order of 1/5 to 1/10 of that energy, but that doesn't change the fact that it is there.

And, BTW, ice cover has increased since 2007... is that a sign of Global Cooling?

Oh, I just love this argument. It's based on the fact that arctic sea ice is declining to unprecedented levels according to studies using every piece of data and proxy data known, as documented in dozens of peer-reviewed studies, but at the same time, Antarctic ice is increasing, and at times, the combined average is higher than the previous combined average. Never mind that Antarctic sea ice increase is a *forecast* of AGW due to the increased snowfall and increase in flow rates of its glaciers, while Artic sea ice is declining, as expected.

The argument can basically be summed up as this:

Nurse: Doctor! The patient in room 1 has a temperature of 103.6! And the temperature of the patient in room 2 is down to 93.6!Doctor: Perfect -- they average out to normal!

If it's about averages, then you have to set the bar for the average. You can say a 30 year average is significant, or a 60 year average, or a 600 year average, or a 6,000 year average. Which are you going to choose? The problem here is we don't have reliable data for the average that may be significant, so no conclusions can be drawn. And how are you going to compare and contrast the Medieval Warming Period (for example), with today's warming? What about the Little Ice Age? Why is your "average" toda

If it's about averages, then you have to set the bar for the average. You can say a 30 year average is significant, or a 60 year average, or a 600 year average, or a 6,000 year average.

No, that would be called "making things up". Statistical significance requires statistical evidence. And we have ample evidence that the planet's temperature is dominated on the inter-annual scale by ENSO, and to a lesser extent, by other factors, but is dominated by AGW on the multi-decadal scale.

We have tons of data on ice extent. Most people know that, back to 1979, we have a beautiful record of satellite readings with only small holes. But there's a lot more.

Before that, we have sailing logs and logs from Arctic cities for the arrival and departure of ice. A particularly good source of data is the records from the US and Soviet navies' submarine fleets, which has been made available to researchers. There's direct written records from sailors all the way back to the dark ages, although these progressively become much patchier and are usually only good for localized ice extent.

From coastal records, the data dates back as far. Starting in the late 1800s, it becomes very good, and is near complete starting in the 1950s. Iceland has a good 1,200 year record.

Probably the best long-term record we have is that of sediment cores, and just recently we've started getting an increasingly number of papers on the subject (due to the hostility of the region, only readily have many cores become available). Here's [googleusercontent.com] a good review. There are several types of sediment proxies.

The first includes the deposition of ice-rafted debris. Large grains of minerals don't just appear in the middle of the ocean. They're too big to blow and too heavy to float. We observe the process of ice rafted debris being deposited in present day. The debris comes in two types: smaller grains from coastal margins, and larger grains from icebergs. The size, shapes, chemical signatures, and surface characteristics of the grains bear hallmarks of their origins and of the type of ice conditions at the time.

A second source of data in sediment cores is that of microfossils. Different types of plankton have different habitats in which they can live (i.e., some can live under ice, others can't) and known sedimentation and preservation rates. A third, and similar, technique involves the fossils of bottom-dwelling organisms. This may seem odd, as they're not directly affected by the ice -- but they're *hugely* indirectly affected. Very little organic matter, which such organisms eat, is deposited beneath the ice sheet; however, vast quantities are deposited around the edges of the ice, and a normal amount beyond it. Their populations are shown to well correlate with ice cover.

A fourth technique, like the above, involves the amount of organic matter itself deposited. Beyond just quantity, you can look at chemistry -- for example, there are chemical biomarkers for diatoms that live in sea ice.

At the coasts, you have a lot more data, as sea ice has significant affects on the land when it touches. This affects everything from whalebone to large mollusks to driftwood to plant matter and so forth. Even arctic tree records provide significant data, as arctic trees do not survive along coasts perennially lined with ice.

Concerning driftwood: wood cannot pass through ice. Driftwood floats, becomes waterlogged, and sinks in open water. Driftwood entrained in sea ice collects in quantity at the ice margin, and corresondingly sinks in quantity at such locations. Massive quantities of driftwood fossils are available.

Various types of sea mammals closely correspond with the ice margins -- polar bears, various species of seals, walrus, narwhal, beluga, and bowhead. T

Which peer reviewed studies of ancient ship logs, naval photography during the 20th century and old newspaper magazines are you referring to?:) I'd be really interested to know how they disagree with me.

Sure -- here's one for starters [metoffice.com], sort of a meta-analysis of other papers. That should be a good jumping-off point for you.

I agree with you that one location is not the arctic ice extent. On the other hand, we only have "one location" (in multiples, depending on the observer) before 1979.

The "data quoted at the end"? What end? It's a looping image (really annoying, by the way). And it's still cherry-picking. Individual ice cores for a single location do not a planetwide temperature average represent; that's what peer-reviewed papers on reconstructions using *all* available data are for.

Not at all. The *reasons* for the warming involve a breakdown of the strength of dozens of different forcings factors, and then looking at them and figuring out why they're changing. I can go into more detail if you'd like.

Sure, 2007 may have been unusual with arctic ice cover well below the trend line (which can be seen halfway down this page [nsidc.org]). This is hardly evidence of a reversal of the trend. GP is correct in describing the continuing decline in arctic ice cover as "unprecedented".

And, BTW, ice cover has increased since 2007... is that a sign of Global Cooling?

The extent of the ice cap is not the only way to measure the ice cover in the arctic. Probably more important is the quality and the volume of the ice [skepticalscience.com] at the polar cap.

By the way, ice 'extent' is different than the 'area' covered by ice. 'Extent' is what is often quoted, not 'area'. Extent is measured like this: If a grid square being examined has more than 15% ice then it is considered ice covered. So if you had two grids being examined of say 10 sq km each, one being covered 80% by ice and the other being 16% covered by ice, the measurements would say that the ice extent or extent of ice coverage is 20 sq km, when the area would be more like 9.6 sq km. Because this is measured by satellite, grids for study are normally more like 25 or more sq km. Argument can be made to use extent over area since sometimes melt water over ice can be interpreted by the analysis software as being open water. Not always but sometimes; so they use extent to be on the safe side.

What many leave out is analysis of data from satellites that provide measurement of ice thickness. The linked web site addresses this somewhat. I have read about and seen information mentioned more and more on this for at least the last five or six years (and to be sure, the real experts have been looking at this for years). It looks like even if the ice extent is greater this year than in 2007, it is still about 1.6 million sq km less than the 1979 to 2000 average; and more importantly, the current volume of arctic ice is the lowest on record.

It's not fair that these guys took the word "skeptical" which is supposed to mean "don't believe in Global Warming, Evolution, Keynesean economics or Obama's birth certificate and made a site that takes global warming seriously.

The majority of scientists in the world that agree that humans are causing climate change (some of which hopefully read Slashdot), or the FOX watching sycophants who lack a basic understanding of science and have the reading comprehension of a gnat? Or are you just one of those people who talk in the third person all the time?

now, I'm still processing all the data for myself on global warming, and have not made my final decision one way or the other. I am leaning towards the idea that anything we do to prevent/correct global warming *That Does Not Cause More Harm If We Are Wrong* is a good idea. That said, I do have this question:
Why is it, when this topic comes up, so many people that are on the side that says human centric global warming is a fact; tend to use the argument that anyone who does not agree with them is a right-wing gun toting SUV driving mentally crippled slack jawed idiot?

Now, I don't pretend that/. is the pinnacle of human communication or anything, but it seems to me that if you want to have a rational discussion abut the subject, and perhaps attract a few more people to your cause (saving the planet from humanity?) then opening with generalizing insults may not be the way to go.

Why is it, when this topic comes up, so many people that are on the side that says human centric global warming is a fact; tend to use the argument that anyone who does not agree with them is a right-wing gun toting SUV driving mentally crippled slack jawed idiot?

Tribalism, mostly. People naturally divide the world into us vs. them on any given subject. While I feel that AGW is the only scientific explanation, most of its supporters are not scientists, much less climate scientists, and many of them jump into fanciful imaginings and impractical plans, doing their cause a great disservice.

Why is it, when this topic comes up, so many people that are on the side that says human centric global warming is a fact; tend to use the argument that anyone who does not agree with them is a right-wing gun toting SUV driving mentally crippled slack jawed idiot?

Because it's patently obvious that humans are the cause of it. It's just an absurd proposition that there is any other significant cause of climate change. Yes, you would have to be some kind a slack-jawed right-wing gun toting idiot, or equivalent, to think otherwise.

You know all this mess in the gulf that people are hysterical about? Imagine 15,000 other deep water oil leaks of the same size spread out across the oceans, and what kind of hell that would be. Because that's the amount of oil we are burning each year. The idea that burning it all instead of letting it leak makes it all but harmless is madness. Less directly harmful that letting it leak, probably, but still plenty bad.

Just being uneducated wouldn't even be enough to explain it. Take a look at yourself for instance. You "haven't made a final decision yet"? Science doesn't make "final decisions". If new facts come up, scientists change the 'decision'; there is no 'final'. The evidence is so overwhelming right now that really the only way to deny it is to un-scientifically hold out for an absolute... well we can't be 100.0% sure so reserve judgment. Mathematics and religion works on absolutes, not science. So it's not even a question of education or intelligence, it's really a question of whether you have to courage to face the facts or not.

I think really the problem is that the scale of human activity is simply too great for many people to comprehend. People that haven't ever left their own town and aren't worldly just don't have the resources or motivation or fortitude to even contemplate it. So I don't hold out much hope for society to change before it's too late. And it's not too late, yet, but we'll need massive infrastructure changes or something drastic like say a solar shield to keep anything resembling our current climate.

The average temperature at the peak of the last glaciation was 8-9C colder than the modern era. In one century, the "business as usual" scenario will lead to over 5-7C warming (our current rate of rise is about 2C per century, but not only are emissions rising, but we're currently having to overcome the planet's thermal inertia).

It's not *that* the temperatures are rising that's the problem. It's the *rate* that's the problem.

I might be dipping my toe in very hot water, but... is it really true that the earth has never warmed this much, this fast in its entire recent history (meaning when large animals of some sort or another were around)? It seems pretty statistically unlikely, but that's just a guess.

Which would be a valid argument if that's what scientists were actually doing. The early 20th century warming is a combination of several factors -- first, a strong shift in the PDO, and then followed by not only a decline in PDO, but a rapid increase in global industrialization. The latter might seem like it would have just the opposite effect, but you have to remember that until the 1960s/1970s, there was very little regulations on power plant emissions. While CO2 causes warming, it has to accumulate for this to happen. Far more rapid is the cooling effects of chemicals like sulfur dioxide, which were emitted en masse until the first world started mandating scrubbers on its power plants. While SOx has a relatively short (compared to CO2) residency, so it's really just a masking of the real climate, its affects are quite powerful.

It's probably true, however unlikely it seems to you, but one of the best proofs doesn't come from animals. Plants don't wander around - Once a tree grows in a spot, it's committed. Some plants in particular drop heavy nuts or seeds that will only get transported as far as animals will move them at the very most, and some spread by runners or similar methods that mean the offspring will always be close to the parent and moving across large distances takes many generations. For one example that's been particularly useful to biologists, evergreens that live on tops of mountains above the deciduous tree line usually stay there unless the climate gets so warm that tree-line moves higher than the mountaintop. Climate change at one rate may let some of these species relocate, but at a faster rate will simply wipe them out locally. In the same way, some plant diseases may spread widely only if the tree-line becomes so low, the mountain peaks are all connected. That's a distinctive, temperature related effect. We can look at plant fossils and make some pretty good estimates of how long it took for prehistoric changes, in particular, there are formulas based on longevity and reproductive frequency that hold if species X stays viable in some area for Y time, the rate of change had to be slower than Z. I't's a pretty good argument if species are now going locally extinct at 10xZ or 50xZ rate, that nothing like that has happened in pre human times, or we wouldn't have living examples of those species. Because some of the currently observed rates can be tens or more times faster than the prehistoric rates, rather than just, say 50% faster, it's considered an unambiguous type of evidence.
To be fair, even this line of reasoning takes a lot of crosschecking. Plenty of legitimate scientific disputes exist over just how big a locale is meaningful, or how many different species should be checked before the results deserve a certain level of confidence, or whether the scars left by a particular plant disease are uniformly distinctive. For some cases, scientists do have to consider other events that may have happened that fast in prehistoric times (Dinos weren't the only thing clobbered by that asteroid 60 million years ago). So, it may be only fair to say, "unless the Cretacious extinctions were really caused by some sort of warming cycle and not a massive shield volcano super-eruption, asteroid impacts, or alien trophy hunters, nothing like this, this fast, has ever happened before." But, within limits such as that, the evidence is mounting.

Why do people always talk about whether the earth will survive, or whether it has survived something like this before? Who cares about this rock. Global warming won't kill the earth; it'll be here long after humanity has gone. It doesn't matter whether earth has gone through this before, because we're not trying to save the earth. We're trying to save us.

What matters is whether the current population of humans can survive a sudden, drastic temperature increase, not whether the earth can.

The early 20th century warming is a combination of several factors -- first, a strong shift in the PDO, and then followed by not only a decline in PDO, but a rapid increase in global industrialization. The latter might seem like it would have just the opposite effect, but you have to remember that until the 1960s/1970s, there was very little regulations on power plant emissions. While CO2 causes warming, it has to accumulate for this to happen. Far more rapid is the cooling effects of chemicals like sulfur dioxide, which were emitted en masse until the first world started mandating scrubbers on its power plants. While SOx has a relatively short (compared to CO2) residency, so it's really just a masking of the real climate, its affects are quite powerful.

During the Younger Dryas, there were large amounts of extinctions throughout N. America, and forests in Scandinavia were replaced with glaciers.

Yes, there have been periods of abrupt climate change in Earth's history that have happened without human involvement. Regardless of cause, they are invariably followed by a large list of bad things happening, with very few good things.

The "Younger Dryas" is only well defined and was only severe within a rather small region -- namely, the tail end of the Gulf Stream. The abrupt termination is likely due to a sudden drop in flow from the Gulf Stream due to a massive, catastrophic disruption of the planet's climate system caused by the draining of a lake holding more water than all of today's lakes combined, after a glacial dam burst. Current data suggests that there was no Younger Dryas event in much of the southern hemisphere, and most

The Younger Dryas was severe in Central and Western Europe and the Eastern, Central and Western parts of North America.

The strongest effects were in Greenland and Iceland. Lesser but still major effects were in western Europe and northeastern North America. There were still lesser ripple affects all across the higher latitudes of the Northern Hemisphere. However, the global average temperature decline during the YD is estimated at only 0.6C. It was a change in heat transport event.

Humans, unfortunately, are not very good at evolving - esp. in modern societies.

Biologically we are not very good at evolving...

We breed rather late in life and we spend a lot of energy on each offspring - probably necessary as humans have so few multiple births. This means there are not that many "experiments" so the opportunity for mutations, both favorable and unfavorable to current or future conditions, are limited. Effective evolution relies on many experiments.

This is quite a bit of bullshit. Evolution is slow, wasteful and undirected. Technology is rapid, efficient and directed. It's stupid to let people die from the cold for generations when you can simply put on a damn coat.

Even worse, we interfere with "natural selection" and actually actively try to eliminate it. The more "advanced" the human society, the more likely we are to keep premature babies alive, mask over various genetic weaknesses with medications and treatments. This results in increasing weakness in each generation as these who avoided the brutal effectiveness of natural selection live to generate yet another even weaker generation.

You make it sound like evolution has a goal, that generations get "weaker" (whatever the hell that means) because of lack of natural selection. Generally, diversity is good (especially if you want evolution as you claim). It should also be pointed out that evolution is not dead; people don'

You have an ID that clearly shows you have been around for a long time. Yet you post such an inanely stupid comment. It's like rationalizing that while humans are directly causing thousands of species to go extinct every year (true), everything will be OK because in a few million years they will just evolve again. Do humans have life spans of 1000s of years? We each live on this planet for a finite amount of time. We now find that we are causing changes to accelerate which will cause us great challenges. Where is my arranging deckchairs on the Titanic analogy, I need it again!

Well, I'm perfectly willing to accept that there have been wide temperature variations in the past. I'm no geologist nor climatologist, but I would have assumed that. However, those variations have do nothing with AWG as far as confirming or denying it.

What I do know is the graphs climatologists present about global warming(like the so-called "hockey stick graph") and the correlation between between such graphs and industrialization is quite troubling.

I actually thought it was one of his better efforts. Even though it is about glaciers he resisted mentioning global warming and provided an imperial to metric conversion for its area.
He also linked to the BBC rather than a 12 page advert laden blog while adding two additional links of his own rather than just posting the story.

Oh and by the way, if you think stories being "about a day late" on slashdot is somehow strange, well then you must be new here...

The areas where the Norwegians settled were warmer than the rest of the area and forested.

"Interpretation of ice core and clam shell data suggests that between 800 and 1300 CE the regions around the fjords of southern Greenland experienced a relatively mild climate several degrees Celsius higher than usual in the North Atlantic, with trees and herbaceous plants growing and livestock being farmed. Barley was grown as a crop up to the 70th degree."

Ah, this old yarn! As another poster has already mentioned, it was named "Greenland" to lure settlers. But more importantly, there *were* places in Greenland that were green. Those same places [hostingprod.com] are still there, and are even bigger today [google.com]. Despite attempts to, the Vikings were unable to grow any crops on Greenland, and the only non-animal sources of food in their diet were wild berries, grasses, and seaweed. Today, Greenland cities can grow beets, rhubarb, and other cold-weather plants that the Vikings we

The author, of course, conflates finding crops growing in modern Greenland to assuming that they could have grown back then, but notes the strong evidence that little, if anything, was ever successfully grown back then but hay and possibly limited amounts of flax (and the only evidence for that is pollen studies, which failed to turn up traditional food crops). Contemporary writings noted that most Greenlanders lived their whole life without ever seeing wheat, a piece of bread, or a mug of barley beer. The earliest settlers reportedly tried growing barley, but there was virtually no success.

Basically, this means flow acceleration would speed up erosion of the corners that "landlock" it relatively quickly. Pressure caused by the increasing flow on the parts that do the "landlocking" could also lead to the iceberg breaking into smaller parts thus making it easier to make it to the open water.

From the data he posted, it doesn't look like the 2000s, or even any multiyear period between 1980-2010 was exceptionally warm in the majority of the measurement sites with a reasonable amount of historical data. That doesn't say anything about globlal warming, but it would seem to suggest that a big iceberg calving in Greenland might not be global warming related. A bigger one calving in 1962 also supports that.

"From the data he posted, it doesn't look like the 2000s, or even any multiyear period between 1980-2010 was exceptionally warm"

The Artic is warming at about 3X the rate of temperate zones, the phenomena is called Polar Amplification [wikipedia.org], it was predicted by one of James Hansens models in the 80's and has since been confirmed by obsevation.

"it would seem to suggest that a big iceberg calving in Greenland might not be global warming related"

Somewhat tautologically the trend that shows AGW is causing ice loss is composed of billions of individual events, none of which can be said to be caused by AGW. It's like thowing dice that are loaded in such a way that the odds of snake's eyes are 10/36 rather than 1/36. You can never say for sure that a particular occurance of snake's eyes was due to the loading, but you can be certain the dice are loaded.